The B - H Curve of a ferromagnetic material is as shown in figure: b Identify the value of retentivity and coercivity from the figure.

Retentively is the ability of a material to resist or to retain magnetic field, and it’s measured by the total strength of a magnetic field that is left in a material when an inducing field is removed from the material. The units in which retentively of a material is measured is Weber per square meter or Weber - 2 . In this digram Ob represents retentively Coercivity is a measurement of a ferromagnetic substance's ability to withstand an external magnetic field without getting demagnetized. The units in which coercivity is measured is ampere per meter and denoted as overset. It’s also known as coercive force or coercive field. In this digram Oc represents Coercivity.

Deduce an expression for magnetic dipole moment of an electron revolving around a nucleus in a circular orbit Indicate the direction of magnetic dipole moment Use the expression to derive the relation between the magnetic moment of an electron moving in a circle and its related angular momentum

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

What do you understand by Permanent magnets and electromagnet? Give uses of electromagnet.

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

State Gauss’ law for magnetism. Explain its significance.

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

State Gauss Law for Magnetism.

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

Assertion: The magnetic field lines are continuous and form closed loops.

Reason: Magnetic monopole does not exist.

The correct option among the following is

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

An electron is moving along

+ x

direction with a velocity of

6 \times 10^{6} {ms}^{- 1}

. It enters a region of uniform electric field of

300 V / c m

pointing along

+ y

direction. The magnitude and direction of the magnetic field set up in this region such that the electron keeps moving along the x direction will be:

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

The $B - H$ Curve of a ferromagnetic material is as shown in figure:

Question Image

A solenoid has a core of a material with relative permeability $400$ . The windings of the solenoid are insulated from the core and carry a current of $2 A$ . If the number of turns is $1000$ Per metre, calculate magnetic intensity $(H)$ and magnetic field $(B)$ .

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

Why magnetic lines of force do not intersect each other?

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

The $B - H$ Curve of a ferromagnetic material is as shown in figure:

Question Image

$(b)$ Identify the value of retentivity and coercivity from the figure.

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

Two short bar magnets of moments

512 A m^{2}

and

1000 A m^{2}

are placed coaxially

18 cm

apart. The magnetic field is zero at a point

Q

between them. The field at

Q

, when one of the magnets is reversed pole to pole is

HARD

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

Which of the field pattern given below is valid for electric field as well as for magnetic field?

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

If a magnet of pole strength

m

is divided into four parts such that the length and width of each small part is half that of initial one, then the pole strength of each parts will be

HARD

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

An electron gun is placed inside a long solenoid of radius

R

on its axis. The solenoid has

n

turns/length and carries a current

I .

The electron gun shoots an electron along the radius of the solenoid with speed

v .

If the electron does not hit the surface of the solenoid, maximum possible value of

v

is (all symbols have their standard meaning):

Question Image

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

A small bar magnet is placed with its axis at

30^{o}

with an external magnetic field of

0.06 T

experiences a torque of

0.018 Nm

. The minimum work required to rotate it from its stable to unstable equilibrium position is:

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

Two identical bar magnets are held perpendicular to each other with a certain separation, as shown below. The area around the magnets is divided into four zones.
Question Image

Given that there is a neutral point it is located in,

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

The midpoints of two small magnetic dipoles of length

d

in end-on positions, are separated by a distance

x, (x > > d)

. The force between them is proportional to

x^{- n}

where

n

is

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

A domain is a ferromagnetic substance is in the form of a cube of side of length

1 μm

. If it contains

8 \times 10^{10}

atoms and each atomic dipole has a dipole moment of

9 \times 10^{- 24}

{Am}^{2}

, then the magnetisation of the domain is

EASY

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

A magnetised wire of magnetic moment 'M' and length '

l

' is bent in the form of a semicircle of radius 'r'. The new magnetic moment is

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

If two identical bar magnets, each of length 'l', pole strength 'm' and magnetic moment 'M' are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is

MEDIUM

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

In a hydrogen atom, the electron moves in an orbit of radius

0.5 Å

making

10^{16}

rps. Calculate the magnetic moment associated with the orbital motion of electron.

HARD

Physical Sciences>Motion and Stability: Forces and Interactions>Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.>Types of Interactions - Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distance between the interacting objects.

Why diamagnetism should be the general property of all materials? Why all substances do not exhibit this?

Deduce an expression for magnetic dipole moment of an electron revolving around a nucleus in a circular orbit. Indicate the direction of magnetic dipole moment? Use the expression to derive the relation between the magnetic moment of an electron moving in a circle and its related angular momentum?

Important Questions on Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.

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